Fine-Tuning in the 2HDM

Abstract

The Two-Higgs Doublet Model (2HDM) is one of the most popular and natural extensions of the Higgs sector; but it has two potential fine-tuning problems, related to the electroweak (EW) breaking and the requirement of alignment with the SM Higgs boson. We have quantified the fine-tunings obtaining analytical expressions, both in terms of the initial 2HDM parameters and the physical ones (masses, mixing angles, etc.). We also provide simple approximate expressions. We have taken into account that the fine-tunings are not independent and removed the "double counting" by projecting the variations of the alignment onto the constant-${\mathrm{v}}^2$ hypersurface. The EW and the alignment fine-tunings become severe in different, even opposite, regions of the parameter space, namely in the regimes of large and small extra-Higgs masses, respectively; emerging an intermediate region, $500\mathrm{GeV}\le \{m_H,m_A,m_{H^{\pm }}\}\le 700\mathrm{GeV}$, where both are acceptably small. We also discuss a remarkable trend that is not obvious at first glance. Namely, for large $\tan \beta$ both the EW and the alignment fine-tunings become mitigated. In consequence, the 2HDM becomes quite natural for $\tan \beta \ge \mathcal{O}(10)$, even if $m_H,m_A,m_{H^{\pm }}$ are as large as 1500 GeV. We explain why this is not the case for the 2HDM stemming from supersymmetry. We have illustrated all these trends by numerically analyzing several representative scenarios.

References in corpus (41)

• Theory and phenomenology of two-Higgs-doublet models
• A Supersymmetry Primer
• Improved Naturalness with a Heavy Higgs: An Alternative Road to LHC Physics
• The CP-conserving two-Higgs-doublet model: the approach to the decoupling limit
• The Inert Doublet Model: an Archetype for Dark Matter
• Combined measurements of Higgs boson production and decay using up to $80$ fb${}^{-1}$ of proton-proton collision data at $\sqrt{s}=$ 13 TeV collected with the ATLAS experiment
• Combined measurements of Higgs boson couplings in proton-proton collisions at $\sqrt{s}=$ 13 TeV
• Note on tree-level unitarity in the General Two Higgs Doublet Model
• The Lightest Higgs Boson Mass in the Minimal Supersymmetric Standard Model
• Models of Yukawa interaction in the two Higgs doublet model, and their collider phenomenology
• The effective potential and the renormalisation group
• Tree-level unitarity constraints in the most general 2HDM
• Dark Matter through the Higgs portal
• Impersonating the Standard Model Higgs Boson: Alignment without Decoupling
• Maximally Symmetric Two Higgs Doublet Model with Natural Standard Model Alignment
• Renormalization Group Improvement of the Effective Potential in Massive O(N) Symmetric ${\varphi }^4$ Theory
• Vacuum Topology of the Two Higgs Doublet Model
• Improving the Effective Potential
• Consistency of the Two Higgs Doublet Model and CP violation in top production at the LHC
• Pseudoscalar Portal Dark Matter
• Scalar sector of Two-Higgs-Doublet models: A mini-review
• Generalized CP symmetries and special regions of parameter space in the two-Higgs-doublet model
• Exclusive Signals of an Extended Higgs Sector
• Distinguishing a MSSM Higgs Boson from the SM Higgs Boson at a Linear Collider
• Geometric picture of generalized-CP and Higgs-family transformations in the two-Higgs-doublet model
• Implications for New Physics from Fine-Tuning Arguments: II. Little Higgs Models
• The effective potential in the presence of several mass scales
• Generalized CP Invariance and the Yukawa sector of Two-Higgs Models
• Cornering the Two Higgs Doublet Model Type II
• Two Higgs Doublet Dark Matter Portal
• Exploring sizable triple Higgs couplings in the 2HDM
• Two-Higgs-doublet models in light of current experiments: a brief review
• Triple Higgs Couplings in the 2HDM: The Complete Picture
• Natural Stabilization of the Higgs Boson's Mass and Alignment
• A natural mechanism for approximate Higgs alignment in the 2HDM
• Bounded masses in Two Higgs Doublets Models, Spontaneous CP Violation and ${\mathbb{Z}}_2$ symmetry
• Natural Alignment in the Two Higgs Doublet Model
• Partially Natural Two Higgs Doublet Models
• Exceptional regions of the 2HDM parameter space
• Higgs alignment and the top quark
• 2HDM singlet portal to dark matter

Cited by in corpus (1)

• Higgs Squared